Battery cell leak inspection device and battery cell leak inspection method

ABSTRACT

An apparatus and a method for inspecting a leak of a battery cell are provided. An apparatus for inspecting a battery cell leak to inspect whether a battery cell leaks includes: a vacuum chamber including an upper chamber and a lower chamber and configured to set a receiving space to a controlled pressure different from an external first pressure, the upper chamber and the lower chamber being arranged to face each other with the receiving space for a battery cell therebetween and providing sealing for the receiving space; a vacuum pipe valve fluidly connected to the receiving space for the battery cell to set the receiving space to a second pressure less than the first pressure; and a thickness measuring sensor configured to measure a before-vacuum thickness of the battery cell under the first pressure and measure an after-vacuum thickness of the battery cell under the second pressure. 
     According to the present disclosure, an apparatus and a method for inspecting a battery cell leak, capable of easily and precisely capturing damage to an exterior material of a battery cell are provided.

TECHNICAL FIELD

The present disclosure relates to an apparatus for inspecting a batterycell leak and a method of inspecting a battery cell leak.

BACKGROUND ART

Unlike a primary battery which is not rechargeable, generally, asecondary battery is rechargeable and dischargeable. A secondary batteryis used as an energy source of mobile apparatuses, electric automobiles,hybrid automobiles, electric bicycles, uninterruptible power supplies,etc., and is used in the form of a single battery cell or a battery packin which a plurality of battery cells are connected and bound in oneunit, depending on the kind of an external apparatus to which the secondbattery is applied.

DESCRIPTION OF EMBODIMENTS Technical Problem

Provided are an apparatus for inspecting a battery cell leak and amethod of inspecting a battery cell leak, capable of easily andprecisely capturing damage to an exterior material of a battery cell.

Technical Solution to Problem

According to an aspect of the present disclosure, an apparatus forinspecting a battery cell leak

to inspect whether a battery cell leaks includes:

a vacuum chamber including an upper chamber and a lower chamber andconfigured to set a receiving space to a controlled pressure differentfrom an external first pressure, the upper chamber and the lower chamberbeing arranged to face each other with the receiving space for a batterycell therebetween and providing sealing for the receiving space;

a vacuum pipe valve fluidly connected to the receiving space for thebattery cell to set the receiving space to a second pressure less thanthe first pressure; and

a thickness measuring sensor configured to measure a before-vacuumthickness of the battery cell under the first pressure and measure anafter-vacuum thickness of the battery cell under the second pressure.

The apparatus may further include a controller configured to determinewhether the battery cell leaks based on a thickness difference betweenthe before-vacuum thickness and the after-vacuum thickness.

As an example, the controller may compare the before-vacuum thicknesswith the after-vacuum thickness and determine that a leak occurs in abattery cell in which swelling occurs.

As an example, the controller may compare a reference value set inadvance with the thickness difference and determine that a leak occursin a battery cell in which a thickness difference exceeding thereference value is measured.

As an example, the apparatus may further include:

a total volatile organic compound (TVOC) pipe valve configured to suckan internal gas from an inside of the receiving space for the batterycell; and

a total volatile organic compound (TVOC) sensor arranged on a suckingflow path of the internal gas to measure a concentration of totalvolatile organic compound from the sucked internal gas.

As an example, the apparatus may further include

a controller configured to synthesize information regarding thebefore-vacuum thickness and the after-vacuum thickness transmitted fromthe thickness measuring sensor and information regarding theconcentration of the total volatile organic compound transmitted fromthe TVOC sensor to determine whether a battery cell leaks.

As an example, the apparatus may further include

a destroy pipe valve configured to set the receiving space for thebattery cell to a third pressure higher than the second pressure,

wherein the TVOC pipe valve may provide a negative pressure lower thanthe third pressure to forcibly suck the internal gas from the inside ofthe receiving space set to the third pressure.

As an example, the receiving space may be provided in plural, and

the vacuum pipe valve, the TVOC pipe valve, and the destroy pipe valvemay be arranged in a position of the upper chamber between the pluralityof receiving spaces, fluidly connected to the plurality of receivingspaces, and may set a pressure shared by the plurality of receivingspaces.

As an example, the thickness measuring sensor may be provided at aposition of the upper chamber that faces the receiving space andarranged to face a battery cell inside the receiving space.

As an example, the thickness measuring sensor may be a non-contact typeeddy current sensor,

wherein an insulating block may be assembled in the upper chamber, theinsulating block surrounding and insulating the thickness measuringsensor.

The thickness measuring sensor may be provided in plural to correspondto the receiving spaces, respectively.

As an example, the first pressure may correspond to the atmosphericpressure.

As an example, a seat jig may be assembled in the lower chamber, aplurality of receiving spaces being provided in the seat jig.

As an example, the apparatus may perform inspection on the seat jigbasis.

According to another aspect of the present disclosure, a method ofinspecting a battery cell leak

using an inspection apparatus including a vacuum chamber and a vacuumpipe valve for controlling a pressure of an inside of the vacuumchamber, the vacuum chamber including an upper chamber and a lowerchamber, includes:

placing a battery cell to an inspection position such that an inspectionstage is provided, in which the upper chamber and the lower chamber arearranged to face each other with a receiving space for the battery celltherebetween;

sealing the receiving space by lowering the upper chamber toward thelower chamber;

maintaining the vacuum pipe valve in an off-state to maintain thereceiving space of the battery cell at a first pressure which is thesame as before the sealing of the vacuum chamber and measuring abefore-vacuum thickness of the battery cell under the first pressure;

switching the vacuum pipe valve to an on-state to set the receivingspace of the battery cell to a second pressure lower than the firstpressure; and

measuring an after-vacuum thickness of the battery cell under the secondpressure.

As an example, the method may further include

determining whether the battery cell leaks based on a thicknessdifference between the before-vacuum thickness and the after-vacuumthickness.

As an example, the determining of whether the battery cell leaks mayinclude comparing the before-vacuum thickness with the after-vacuumthickness and determining that a leak occurs in the battery cell inwhich swelling occurs.

As an example, the method may further include

switching a destroy pipe valve fluidly connected to the receiving spacefor the battery cell to an on-state to set the receiving space to athird pressure higher than the second pressure; and

forcibly sucking an internal gas from an inside of the receiving spaceset to the third pressure and measuring a concentration of totalvolatile organic compound from the sucked internal gas.

As an example, the method may further include

synthesizing a thickness difference between the before-vacuum thicknessand the after-vacuum thickness, and the concentration of the totalvolatile organic compound to determine whether the battery cell leaks.

As an example, the placing of the battery cell to the inspectionposition may include

assembling a seat jig in the lower chamber, receiving spaces for aplurality of battery cells being provided in the seat jig; and

moving the lower chamber receiving the plurality of battery cells to awaiting position of the upper chamber.

As an example, the method may further include

raising the upper chamber in a direction away from the lower chamber todischarge an inspection-completed battery cell.

Advantageous Effects of Disclosure

According to the present disclosure, whether an exterior material of abattery cell is damaged may be precisely and easily captured bycalculating a thickness difference between a before-vacuum thickness andan after-vacuum thickness of the battery cell under different pressures,and determining that a battery cell in which swelling occurs is adefective product in which a leak occurs based on the calculatedthickness difference.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view of an apparatus for inspecting a battery cell leakaccording to an embodiment.

FIG. 2 is a view of an apparatus for inspecting a battery cell leakshown in FIG. 1, for explaining a transfer operation of placing abattery cell to an inspection stage in the apparatus for inspecting abattery cell leak shown in FIG. 1.

FIG. 3 is a view for explaining a transfer operation of placing abattery cell to an inspection stage in the apparatus for inspecting abattery cell leak shown in FIG. 1 and is a view for explaining amodified embodiment of FIG. 2.

FIG. 4 is a perspective view of a battery cell which is an inspectionobject of the apparatus for inspecting a battery cell according to anembodiment.

FIG. 5 is a process flowchart of a method of inspecting a leak.

FIGS. 6 to 8 are views of driving of an apparatus for inspecting a leakapplied to the method of inspecting a leak, and FIGS. 7 and 8 arecross-sectional views of an apparatus for inspecting a leak, taken alongline VII-VII of FIG. 6.

FIG. 9 is a view showing, for each process, valve ON/valve OFFoperations of various pipe valves VA, VT, and R of an apparatus forinspecting a leak shown in FIG. 8.

BEST MODE

According to an aspect of the present disclosure, an apparatus forinspecting a battery cell leak

to inspect whether a battery cell leaks includes:

a vacuum chamber including an upper chamber and a lower chamber andconfigured to set a receiving space to a controlled pressure differentfrom an external first pressure, the upper chamber and the lower chamberbeing arranged to face each other with the receiving space for a batterycell therebetween and providing sealing for the receiving space;

a vacuum pipe valve fluidly connected to the receiving space for thebattery cell to set the receiving space to a second pressure less thanthe first pressure; and

a thickness measuring sensor configured to measure a before-vacuumthickness of the battery cell under the first pressure and measure anafter-vacuum thickness of the battery cell under the second pressure.

According to another aspect of the present disclosure, a method ofinspecting a battery cell leak

using an inspection apparatus including a vacuum chamber and a vacuumpipe valve for controlling a pressure of an inside of the vacuumchamber, the vacuum chamber including an upper chamber and a lowerchamber, includes:

placing a battery cell to an inspection position such that an inspectionstage is provided, the upper chamber and the lower chamber are arrangedto face each other with a receiving space for the battery celltherebetween in the inspection stage;

sealing the receiving space by lowering the upper chamber toward thelower chamber;

maintaining the vacuum pipe valve in an off-state to maintain thereceiving space of the battery cell in a first pressure as beforesealing of the vacuum chamber and measuring a before-vacuum thickness ofthe battery cell under the first pressure;

switching the vacuum pipe valve to an on-state to set the receivingspace of the battery cell to a second pressure less than the firstpressure; and

measuring an after-vacuum thickness of the battery cell under the secondpressure.

MODE OF DISCLOSURE

Hereinafter, an apparatus for inspecting a leak of a battery cell Baccording to an embodiment is described with reference to theaccompanying drawings.

FIG. 1 is a view of an apparatus for inspecting a battery cell leakaccording to an embodiment. FIG. 2 is a view of an apparatus forinspecting a battery cell leak shown in FIG. 1, for explaining atransfer operation of placing a battery cell to an inspection stage inthe apparatus for inspecting a battery cell leak shown in FIG. 1. FIG. 3is a view for explaining a transfer operation of placing a battery cellto an inspection stage in the apparatus for inspecting a battery cellleak shown in FIG. 1 and is a view for explaining a modified embodimentof FIG. 2.

Referring to the drawings, the apparatus for inspecting a leak of abattery cell B may include a vacuum chamber VC and various pipe valvesVA, VT, and R, the vacuum chamber VC including an upper chamber UC and alower chamber LC arranged to face each other with a receiving space Gfor the battery cell B therebetween, and the various pipe valves VA, VT,and R on/off-operating to set the receiving space G for the battery cellB to a controlled pressure different from an external first pressure orto forcibly suck an internal gas from the inside of the receiving spaceG for the battery cell B. In addition, the apparatus for inspecting aleak of a battery cell B may include a thickness measuring sensor TS anda total volatile organic compound (TVOC) sensor VTS, the thicknessmeasuring sensor TS being configured to measure a before-vacuumthickness of the battery cell B and an after-vacuum thickness of thebattery cell B, and the TVOC sensor VTS being arranged on a suction flowpath to measure the concentration of total volatile organic compoundTVOC from an internal gas forcibly sucked from the inside of thereceiving space G of the battery cell B. In addition, the apparatus forinspecting a leak of a battery cell B may include a controller 100configured to generally control the operations of the vacuum chamber VC,the various pipe valves VA, VT, and R, the thickness measuring sensorTS, and the TVOC sensor VTS, receive measurement results of thethickness measuring sensor TS and the TVOC sensor VTS, and determinewhether the battery cell B leaks based on the measurement results.

The vacuum chamber VC may provide sealing for maintaining a secondpressure (a vacuum pressure) relatively lower than the first pressurecorresponding to the atmospheric pressure. The apparatus for inspectinga leak according to an embodiment determines whether the battery cell Bleaks by capturing swelling of the battery cell B under the secondpressure (the vacuum pressure) lower than the first pressure (ex. theatmospheric pressure), and, for this purpose, may measure the thicknessof the battery cell B in the vacuum chamber VC in which the vacuumpressure may be maintained. That is, the apparatus for inspecting a leakaccording to an embodiment may measure a before-vacuum thickness underthe first pressure, measure an after-vacuum thickness under the secondpressure, calculate a thickness difference between the before-vacuumthickness and the after-vacuum thickness, and determine that a batterycell B in which swelling occurs is a defective product in which a leakoccurs based on the calculated thickness difference.

Since the vacuum chamber VC provides sealing of the receiving space forthe battery cell B, the pressure of the receiving space G may be easilycontrolled, and as described below, setting of the vacuum lower than thefirst pressure (ex. the atmospheric pressure) and destruction of thevacuum may be easily controlled depending on each operation of the leakinspection.

Throughout the present specification, the first pressure may correspondto the atmospheric pressure, which is an external pressure of the vacuumchamber VC. Even in the state in which the upper chamber UC and thelower chamber LC are in close contact with each other, under a state inwhich the various pipe valves VA, VT, and R that are fluidly connectedto the receiving space G of the battery cell B do not operate, thereceiving space G of the battery cell B may be maintained at the firstpressure. The second pressure is a vacuum state lower than the firstpressure and may correspond to a pressure of a state in which the upperchamber UC and the lower chamber LC are in close contact with each otherand thus the vacuum chamber VC is sealed, and the vacuum pipe valve VAfluidly connected to the receiving space G for the battery cell B isswitched to an on-state to set the receiving space for the battery cellB to vacuum.

The upper chamber UC and the lower chamber LC may be driven to approacheach other or to be spaced apart from each other with the receivingspace G for the battery cell B therebetween. As an example, the upperchamber UC may descend toward the lower chamber LC and be in closecontact with the lower chamber LC at a preset pressure to seal thevacuum chamber VC and seal the receiving space G for the battery cell Bfrom the outside. In addition, the upper chamber UC may ascend away fromthe lower chamber LC to open the vacuum chamber VC and expose thereceiving space G for the battery cell B to the outside.

The apparatus for inspecting a leak according to an embodiment isapplicable to a successive inspection method in which, while a batterycell B, which is an inspection object, is successively supplied in onedirection (a back-and-forth direction), an inspection-completed batterycell B is discharged and an inspection object is moved to the nextbattery cell B. As an example, one of the upper chamber UC and the lowerchamber LC may be driven in one direction (the back-and-forth direction)to move an inspection stage IS from an inspection-completed battery cellB to the next battery cell B, and the other of the upper chamber UC andthe lower chamber LC waits for the one of the chambers in the inspectionstage IS. In addition, the upper chamber UC and the lower chamber LCarranged to face each other in the inspection stage IS approach eachother and are in close contact with each other to seal the receivingspace G (sealing of the vacuum chamber VC). In the sealed receivingspace G, a pressure thereof may be easily controlled under control ofthe controller 100, and the pressure may be set to the second pressureof the vacuum lower than the first pressure (ex. the atmosphericpressure), or set to the third pressure (ex. the atmospheric pressure)higher than the second pressure with the vacuum destroyed. In addition,an inspection-completed battery cell B may be discharged, and one of theupper chamber UC and the lower chamber LC may be driven in a direction(the back-and-forth direction) away from each other to move theinspection stage IS to the next battery cell B. With the receiving spaceG open, the inspection-completed battery cell B may be discharged, andone of the upper chamber UC and the lower chamber LC may move toward abattery cell B, which is the next inspection object.

In an embodiment shown in FIG. 2, the lower chamber LC may be driven inone direction (the back-and-forth direction) and may serve as a transfermeans supplying a battery cell B, which is an inspection object. Thelower chamber LC may receive a plurality of battery cells B and supply abattery cell BB to the inspection stage IS in which the upper chamber UCwaits.

In an embodiment shown in FIG. 3, the upper chamber UC may be driven inone direction (the back-and-forth direction) and driven in one direction(the back-and-forth direction) toward the inspection stage IS in whichthe lower chamber LC waits, a battery cell B, which is an inspectionobject, being seated on the lower chamber LC. The upper chamber UC mayperform leak inspection on the battery cell B waiting together with thelower chamber LC in the inspection stage IS.

Referring to FIG. 1, a seat jig ZG including the receiving space G forthe plurality of battery cells B may be assembled to the lower chamberLC. A jig groove may be formed in the lower chamber LC, the seat jig ZGbeing assembled to the jig groove. The seat jig ZG may be adaptivelyprovided depending on the shape and the size of the battery cell B,which is an inspection object. For this purpose, the seat jig ZG may bevariously prepared to have the receiving spaces G of various shapes andsizes. In addition, through a simple operation of replacing the seat jigZG inside the lower chamber LC while using the same upper chamber UC andthe same lower chamber LC, a leak inspection may be performed on thebattery cells B of various sizes and shapes. In the present disclosure,to perform a leak inspection on battery cells B of various sizes andshapes, leak inspection apparatuses of various shapes are notindividually required. Instead, one leak inspection apparatus is used toperform a leak inspection on battery cells B of various sizes and shapesby replacing with a matching seat jig ZG according to various sizes andshapes.

For assembling between the seat jig ZG and the lower chamber LC, aposition alignment means may be provided to the seat jig ZG and thelower chamber LC. As an example, a position alignment pin A may beformed in the lower chamber LC, and a position alignment groove may beformed in the seat jig ZG to prevent misalignment between the lowerchamber LC and the seat jig ZG. As an example, the position alignmentpin A and the position alignment groove may be formed on the left andright around the center of the lower chamber LC and the seat jig ZG.

The seat jig ZG and the lower chamber LC may be fixed in position withrespect to each other. As an example, a bolt as a fixing means F may befastened to the seat jig ZG. The fixing means F may pass through theseat jig ZG and be fastened to the lower chamber LC to fix the seat jigZG and the lower chamber LC in position with each other.

The seat jig ZG may include an insulating material to insulate thebattery cell B, not to generate an electric short-circuit even whencontacting the battery cell B, and to block an electric interferencewith the battery cell B.

The receiving space G that may receive the battery cell B may beprepared in the seat jig ZG. The receiving space G for the battery cellB may be formed in a size such that a clearance of 0.5 mm to 1 mm may besecured greater than the external shape of the battery cell B not todamage the battery cell B, particularly an exterior material BP (seeFIG. 4) of the battery cell B due to physical interference with thebattery cell B during attachment/detachment of the battery cell B whilesolidly fixing the battery cell B in position. An edge portion of thereceiving space G for the battery cell B may be round-processed suchthat defects such as starches or chopping may not be caused to thebattery cell B, particularly, the exterior material BP (see FIG. 4) ofthe battery cell B due to physical interference or friction with thebattery cell B.

The seat jig ZG may include a plurality of receiving spaces G which mayrespectively receive a plurality of battery cells B. The apparatus forinspecting a leak according to an embodiment does not perform a leakinspection on a battery cell B basis but may perform a leak inspectionon a seat jig ZG basis. The apparatus for inspecting a leak according toan embodiment may simultaneously perform a leak inspection on aplurality of battery cells B by performing a leak inspection in unit ofa seat jig ZG which receives a plurality of battery cells B.Accordingly, a process time for performing a leak inspection on theplurality of battery cells B may be reduced. As an example, one seat jigZG may receive a plurality of battery cells, for example, 20 batterycells B simultaneously.

When the lower chamber LC that receives the plurality of battery cells Bis transferred to the inspection stage IS facing the upper chamber UC,the upper chamber UC that is waiting may descend toward the lowerchamber LC. The upper chamber UC may be in close contact with the lowerchamber LC to seal the receiving space G (sealing of the vacuum chamberVC) inside the lower chamber LC (more specifically, the seat jig ZGassembled to the lower chamber LC). A first sealing member S1 may bearranged between the lower chamber LC and the upper chamber UC. Sincethe lower chamber LC and the upper chamber UC are in contact with eachother at a preset pressure with the first sealing member S1therebetween, pressure leakage of the receiving space G may be blocked.As an example, the first sealing member S1 may be buried in the sealinggroove of the lower chamber LC and may protrude from the sealing grooveof the lower chamber LC to a preset height to be in close contact withthe upper chamber UC at a preset pressure, thereby sealing between theupper chamber UC and the lower chamber LC. As an example, the firstsealing member S1 may be provided as an O-ring.

Various kinds of pipe valves VA, VT, and R for controlling the pressureof the receiving space G may be mounted on the upper chamber UC. Thepipe valves VA, VT, and R may be fluidly connected to the receivingspace G closed by the upper chamber UC and the lower chamber LC and mayadjust the pressure of the receiving space G under control of thecontroller 100.

More specifically, the pipe valves VA, VT, and R may include the vacuumpipe valve VA, the TVOC pipe valve VT, and the destroy pipe valve R. Thepipe valves VA, VT, and R may be periodically driven with differentstarting periods and different ending periods as each operation of theleak inspection is repeated. More specifically, the vacuum pipe valve VAmay operate to set vacuum and provide a negative pressure to thereceiving space G closed by the upper chamber UC and the lower chamberLC to set the pressure of the receiving space G to the second pressureof the vacuum lower than the first pressure (ex. the atmosphericpressure).

To measure TVOC, the TVOC pipe valve VT may provide a negative pressureto suck an internal gas of the receiving space G from the inside of thereceiving space G closed by the upper chamber UC and the lower chamberLC. During the TVOC measuring operation, to capture the total volatileorganic compound (TVOC) filling the inside of the receiving space G, theTVOC pipe valve VT is driven to suck an internal gas of the receivingspace G. The total volatile organic compound (TVOC) may be captured byusing the TVOC sensor VTS arranged on a suction flow path of theinternal gas.

The destroy pipe valve R is driven to an on-state before the TVOCmeasurement and may destroy the vacuum state such that suction of theinternal gas may be performed for TVOC measurement. As an example, thedestroy pipe valve R may be switched to an on-state while the receivingspace G for the battery cell B is set to the second pressure of thevacuum and may set the pressure of the receiving space G to the thirdpressure higher than the second pressure. As an example, the destroypipe valve R may set the pressure inside the receiving space G to thethird pressure (ex. the atmospheric pressure) by connecting the insideto the outside of the receiving space G such that the vacuum of thereceiving space G closed by the upper chamber UC and the lower chamberLC is released. As the TVOC pipe valve VT is switched to an on-state toprovide a negative pressure lower than the third pressure (ex. theatmospheric pressure) during the TVOC measuring operation after thevacuum destruction, the destroy pipe valve R may allow the internal gasof the receiving space G to be forcibly introduced to the suction flowpath at which the TVOC sensor VTS is arranged. When the vacuumdestruction does not precede, to suck the internal gas of the receivingspace G under the second pressure of vacuum, a negative pressurerelatively lower than the second pressure needs to be provided duringthe TVOC measuring operation, and an excessive burden may be put on thedriving power of the inspection apparatus. Therefore, it is preferablethat the TVOC measurement is performed after the vacuum destruction.

The pipe valves VA, VT, and R may be mounted on the upper chamber UC.More specifically, the pipe valves VA, VT, and R may act in common fordifferent receiving spaces G and be provided at positions betweendifferent receiving spaces G to provide a balanced pressure for thedifferent receiving spaces G. As an example, the different receivingspaces G may be sealed from the outside by being surrounded by the firstsealing member S1 arranged between the upper chamber UC and the lowerchamber LC, and fluidly connected to each other, and the pressures ofthe different receiving spaces G may be controlled by the pipe valvesVA, VT, and R installed between the different receiving spaces G.

The thickness measuring sensor TS for capturing swelling of the batterycell B may be mounted on the upper chamber UC. In the presentembodiment, the thickness measuring sensor TS may include both a contacttype sensor that physically contacts the external surface of the batterycell B to measure a thickness thereof, and a non-contact type sensorthat does not physically contact the external surface of the batterycell B to measure a thickness thereof. As an example, the contact typesensor may include an indicator, and the non-contact type sensor mayinclude an eddy current sensor, a fiber sensor, a laser sensor, and avision sensor.

The thickness measuring sensor TS may be assembled to the upper chamberUC and may approach toward the battery cell B or may be raised orlowered to be away from the battery cell B by a separate driving means(not shown) such that the thickness measuring sensor TS may be drivenindependently of the upper chamber UC. As an example, the thicknessmeasuring sensor TS may be raised or lowered to directly contact thebattery cell B and measure the thickness of the battery cell B, orraised or lowered to maintain a measurable distance sufficient tomeasure the thickness of the battery cell B even though not directlycontacting the battery cell B.

As an example, the thickness measuring sensor TS may include anon-contact type eddy current sensor. The eddy current sensor may bearranged inside an insulating block IB to electrically insulate the eddycurrent sensor and avoid a measurement error due to electricinterference. That is, for electric insulation, the thicknessmeasurement sensor TS may be surrounded by the insulating block IB andassembled inside the upper chamber UC together with the insulating blockIB. In this case, to block the leakage of vacuum through a gap betweenthe insulating block IB and the upper chamber UC, a second sealingmember S2 may be arranged at a boundary between the insulating block IBand the upper chamber UC.

The thickness measuring sensor TS may be mounted in plural to correspondto the number of receiving spaces G at positions corresponding to thedifferent receiving spaces G. The thickness measuring sensor TS maymeasure the thickness of each battery cell B received in each receivingspace G. The thickness measuring sensor TS may measure the thickness ofthe battery cell B before and after vacuum and capture whether swellingoccurs based on the change of the measured thickness.

More specifically, the thickness measuring sensor TS may be drivenaccording to a control signal of the controller 100, may compare abefore-vacuum thickness with an after-vacuum thickness through twothickness measurements for the same battery cell B, and determine thatthe battery cell B in which an increase in thickness is captured is abattery in which a leak occurs.

FIG. 4 is a perspective view of a battery cell which is an inspectionobject of the apparatus for inspecting a leak according to anembodiment.

Referring to the drawing, the apparatus for inspecting a leak accordingto an embodiment may treat a battery cell B as an inspection object. Thebattery cell B may include an electrode assembly BC and an exteriormaterial BP in which the electrode assembly BC is received. The exteriormaterial BP may include a flexible exterior material BP such as a pouchand include an insulating layer (not shown) formed on two opposite sidesof a metal thin plate (not shown). The exterior material BP may beformed to a thin thickness of 1 mm scale, and damage such as scratchesof the exterior material BP or tearing of the exterior material BP mayoccur during forming of the exterior material BP such as drawing orpacking of the electrode assembly BC using the exterior material BP.When damage occurs to the exterior material BP, a leak phenomenon mayoccur in which an external impurity gas flows into the battery cell Bthrough the damaged exterior material BP due to a pressure differencebetween the inside and outside of the battery cell B. Since a pressureinside the exterior material BP, that is, an inner pressure of thebattery cell B is set to a vacuum pressure lower than the atmosphericpressure, when a leak occurs, an external impurity gas penetrates intothe battery cell B, and simultaneously with the occurrence of a leak,the inner pressure of the battery cell B is raised to a pressure of theatmospheric pressure level from the vacuum pressure lower than theatmospheric pressure due to the penetration of the external impuritygas.

The apparatus for inspecting a leak according to an embodiment measuresthe thickness T (a before-vacuum thickness) of the battery cell B beforevacuum is set, that is, under a first pressure (ex. the atmosphericpressure), and measures the thickness T (an after-vacuum thickness) ofthe battery cell B under a second pressure lower than the first pressure(ex. the atmospheric pressure) inside the receiving space G for thebattery cell B sealed by the upper chamber UC and the lower chamber LC.A difference between the before-vacuum thickness and the after-vacuumthickness does not occur to a normal battery cell B in which a leak doesnot occur. In a normal battery cell B, since any of the first pressure(ex. the atmospheric pressure) before the vacuum and the second pressureafter the vacuum is still greater than the inner pressure of the batterycell B, the battery cell B is subjected to compression pressure thattends to shrink the battery cell B from the outside, and as a result,swelling does not occur and there is no change in thickness before andafter vacuum. In contrast, in a defective battery cell B in which a leakoccurs, swelling occurs due to a pressure change before and aftervacuum, and as a result, a difference between a before-vacuum thicknessand an after-vacuum thickness occurs. That is, in a defective batterycell B, an external impurity gas penetrates into the battery cell B dueto the damage such as starches or tearing of the exterior material BPand the inner pressure of the battery cell B is raised to theatmospheric pressure higher than an initially set inner pressure or alevel close to the atmospheric pressure. In this case, in a defectivebattery cell B, no special abnormalities may not be captured under thefirst pressure (ex. the atmospheric pressure) before vacuum, but underthe second pressure lower than the first pressure (ex. the atmosphericpressure), the inner pressure (the atmospheric pressure due to thedamage of the exterior material BP) of the battery cell B is higher thanthe external pressure (the second pressure, a vacuum pressure). Swellingin which the battery cell B expands occurs due to the pressuredifference between the inside and outside of the battery cell B. Forthis reason, in a defective battery cell B, a thickness after vacuumincreases compared to a thickness before vacuum. Determining whether thebattery cell B is defective may be made based on a thickness changebefore and after vacuum.

The thickness before vacuum may denote the thickness T of the batterycell B measured under the relatively high first pressure (ex. theatmospheric pressure) before vacuum is set. The thickness T of thebattery cell B may be measured with a direction perpendicular to aprimary surface of the battery cell B, that is, the primary surface thatoccupies a largest area of the battery cell B as a thickness direction.In this case, the thickness before vacuum may be measured under therelatively high first pressure (ex. the atmospheric pressure) beforevacuum is set. Even when the upper chamber UC and the lower chamber LCare in close contact with each other and thus the vacuum chamber VC issealed, while the various pipe valves VA, VT, and R fluidly connected tothe receiving space G for the battery cell B do not operate, thereceiving space G for the battery cell B may be maintained at the firstpressure (ex. the atmospheric pressure) that is the same as the outsideof the vacuum chamber VC. Even right after the upper chamber UC and thelower chamber LC are sealed, as long as the various pipe valves VA, VT,and R do not operate, the receiving space G for the battery cell Bbetween the upper chamber UC and the lower chamber LC may still maintainthe same pressure as the first pressure (ex. the atmospheric pressure)of the outside of the vacuum chamber VC.

The before-vacuum thickness of the battery cell B may be measured undera state in which the upper chamber UC and the lower chamber LC eachproviding sealing for the receiving space G are in close contact witheach other to face each other and thus the vacuum chamber VC is sealed,and vacuum of the receiving space G is not set by the vacuum pipe valveVA. The upper chamber UC and the lower chamber LC may be in closecontact with each other for measurement of thicknesses before and aftervacuum, and the thickness measuring sensor TS mounted on the upperchamber UC may perform the thickness measurement on the battery cell Barranged to face the thickness measuring sensor TS inside the lowerchamber LC according to a control signal of the controller 100. That is,while the thickness measuring sensor TS and the battery cell B arearranged to face each other at corresponding positions of the upperchamber UC and the lower chamber LC, thickness measurement before vacuummay be performed.

The thickness after vacuum may denote the thickness T of the batterycell B measured under the relatively low second pressure after vacuum isset, and the thickness T of the battery cell B may be measured with adirection perpendicular to the primary surface of the battery cell B asa thickness direction. In this case, the thickness after vacuum may bemeasured under the relatively low second pressure after vacuum is set,for example, under a vacuum pressure lower than the first pressure (ex.the atmospheric pressure). The thickness after vacuum may be measuredunder a state in which the upper chamber UC and the lower chamber LCeach providing sealing for the receiving space G are in close contactwith each other to face each other and vacuum for the receiving space Gis set and maintained by the vacuum pipe valve VA. The upper chamber UCand the lower chamber LC may be in close contact with each other forthickness measurement before and after vacuum, and the thicknessmeasuring sensor TS mounted on the upper chamber UC may performthickness measurement on the battery cell B arranged to face thethickness measuring sensor TS inside the lower chamber LC according to acontrol signal of the controller 100. That is, the thickness aftervacuum may be measured at positions where the thickness measuring sensorTS and the battery cell B are arranged to face each other in the upperchamber UC and the lower chamber LC.

The apparatus for inspecting a leak according to an embodiment maydetermine whether the battery cell B leaks by capturing the swelling ofthe battery cell B. In addition, the apparatus for inspecting a leakaccording to an embodiment may more precisely determine whether thebattery cell B leaks by measuring the concentration of total volatileorganic compound (TVOC) (referred to as TVOC measurement hereinafter) ofa gas forcibly sucked from the receiving space G of the battery cell B.As an example, the apparatus for inspecting a leak according to anembodiment may include both a configuration for measuring the swellingof the battery cell B and a configuration for TVOC measurement. The leakinspection using the apparatus according to an embodiment may mainlyperform swelling measurement of the battery cell B, additionally performconcentration measurement of total volatile organic compound (TVOC), andprecisely determine whether the battery cell B leaks based on themeasurement results.

The TVOC measurement may be performed after the swelling measurement ofthe battery cell B. More specifically, the TVOC measurement may beperformed after destroying the vacuum atmosphere for measuring theswelling of the battery cell B. In the TVOC measurement, since a suctionpressure provided at a relatively low pressure is provided to thereceiving space G for the battery cell B, an internal gas of thereceiving space is sucked and the TVOC sensor VTS arranged on a suctionpath of the internal gas is operated and accordingly, the TVOCconcentration may be measured from the sucked internal gas. For thispurpose, in the TVOC measurement operation, the TVOC pipe valve VTconnected to the receiving space G of the battery cell B is switched toan on-state, and the internal gas of the receiving space G may beallowed to flow to the TVOC sensor VTS through the TVOC pipe valve VTthrough a fluid pump (not shown) fluidly connected to the TVOC pipevalve VT. The TVOC sensor VTS may be arranged on a flow path of theinternal gas sucked from the inside of the receiving space G to measurethe concentration of the TVOC from the sucked internal gas.

Electrolyte (not shown) may be received inside the battery cell Btogether with the electrode assembly BC (see FIG. 4), and theelectrolyte (not shown) may include volatile organic compound. In thiscase, an organic compound component of an electrolyte may be extractedfrom an internal gas sucked from a defective battery cell B in which anexterior material BP (see FIG. 4) is damaged, or the receiving space Gin which a defective battery cell B is received. The organic compoundcomponent of the electrolyte is not extracted from an internal gassucked from a normal battery cell B in which an exterior material BP(see FIG. 4) is good, or the receiving space G in which a normal batterycell B is received. Accordingly, the TVOC concentration measured in theTVOC operation may provide a reference for determining whether thebattery cell B leaks.

The above-described measurements of the thicknesses before vacuum andafter vacuum for the battery cell B, that is, the swelling measurementof the battery cell B may be individually performed on each battery cellB, and the TVOC measurement may be performed in unit of a seat jig ZG.As an example, even when battery cells B are determined as beingdefective based on the TVOC results, whether a battery cell B is adefective battery cell among the plurality of battery cells Bconstituting a unit of the seat jig ZG may be determined based onwhether swelling occurs in each battery cell B. In the leak inspectionof a battery cell B to which the apparatus according an embodiment isapplied, swelling measurement of the battery cell B is mainly performedand TVOC measurement may be additionally performed. Whether eachindividual battery cell B leaks may be determined depending on whetherswelling is captured.

More specifically, in the TVOC measurement, a TVOC concentration ismeasured for an internal gas sucked from a plurality of battery cells Breceived in the same seat jig ZG. The internal gas forcibly suckedthrough the TVOC pipe valve VT corresponds to a total sum of internalgases sucked from different receiving spaces G. As an example, this isbecause the different receiving spaces G may be fluidly connected toeach other inside the first sealing member S1 that seals between theupper chamber UC and the lower chamber LC, and suction for the differentreceiving spaces G may be performed through the TVOC pipe valve VTarranged between these receiving spaces G.

The TVOC measurement is performed after vacuum setting that sets thepressure of the receiving space G in which the battery cell B isreceived to the second pressure, which is vacuum, and vacuum destroying.Accordingly, the TVOC measurement may be performed with an externalimpurity gas removed from the receiving space G of the battery cell B.In the vacuum destroy operation, even when the destroy pipe valve R isswitched to an on-state and the vacuum chamber VC is set to therelatively high third pressure (ex. the atmospheric pressure) byconnecting the inside and the outside of the vacuum chamber VC to eachother, external air may flow into the vacuum chamber VC throughfiltering of the destroy pipe valve R such that an external impurity gasis not introduced to the inside of the vacuum chamber VC. Accordingly,in the TVOC measurement, only volatile organic compound due to thedamage of the battery cell B may be captured with an influence of anexternal impurity gas, particularly, a volatile organic compound flowingfrom the outside minimized.

In the measurement of a thickness after vacuum for determining whetherswelling occurs in the battery cell B, the pressure of the receivingspace G in which the battery cell B is received is set to the secondpressure of vacuum lower than the first pressure (ex. the atmosphericpressure). In this case, the second pressure may be set lower than theatmospheric pressure corresponding to the first pressure and set higherthan an inner pressure of a normal battery cell B in which a leak doesnot occur. This is because, when the second pressure set in themeasurement of a thickness after vacuum is set lower than an innerpressure of a normal battery cell B in which an exterior material BP isnot damaged, swelling occurs to all battery cells B withoutdiscrimination between a normal battery cell and a defective batterycell and thus a battery cell cannot be determined as normal or defectivebased on whether swelling occurs. In an embodiment, the second pressuremay be set lower than the atmospheric pressure, which is the firstpressure, and higher than the inner pressure of a normal battery cell Bin which a leak does not occur. As an example, the second pressure maybe set lower than 760 torr, which is the atmospheric pressure, andwithin a range higher than 10 torr, which is the inner pressure of anormal battery cell B, that is, within a range of 10 torr to 760 torr.

Hereinafter, the method of inspecting a leak according to an embodimentis described for each process operation.

FIG. 5 is a process flowchart of a method of inspecting a leak. FIGS. 6to 8 are views of driving of an apparatus for inspecting a leak appliedto the method of inspecting a leak, and FIGS. 7 and 8 arecross-sectional views of the apparatus for inspecting a leak, takenalong line VII-VII of FIG. 6. FIG. 9 is a view showing, for eachprocess, valve ON/valve OFF operations of various pipe valves VA, VT,and R of the apparatus for inspecting a leak shown in FIG. 8.

Referring to FIG. 5, leak inspection to which the apparatus according toan embodiment is applied may include a product placing operation S10, avacuum chamber sealing operation S20, a before-vacuum thicknessmeasuring operation S30, a vacuum setting operation S40, an after-vacuumthickness measuring operation S50, a vacuum destroy operation S60, aTVOC measuring operation S70, a normal/defective product determiningoperation S80, a vacuum chamber opening operation S90, and a productdischarging operation S100.

Referring to FIG. 6, in the product placing operation S10, the lowerchamber LC may be driven in one direction (the back-and-forth direction)to supply a battery cell B toward the inspection stage IS and dischargean inspection-completed battery cell B. The lower chamber LC thatreceives a plurality of battery cells B may serve as a transfer meansthat approaches toward the inspection stage IS over which the upperchamber UC waits to supply the battery cell B, and is driven in onedirection (the back-and-forth direction) to be away from the inspectionstage IS after the inspection is completed to discharge aninspection-completed battery cell B.

As an example, the product placing operation S10 may include anoperation of assembling the seat jig ZG in which the receiving spaces Gfor a plurality of battery cells B is prepared to the lower chamber LC,and an operation of moving the lower chamber LC in which the pluralityof battery cells B are received to a waiting position of the upperchamber UL.

As an example, the upper chamber UC may wait for the lower chamber LCover the inspection stage IS at a set position in one direction (theback-and-forth direction), descend in a direction facing the lowerchamber LC with respect to the lower chamber LC that approaches theinspection stage IS that faces the upper chamber UC, and be in closecontact with the lower chamber LC.

The seat jig ZG in which the plurality of battery cells B are receivedinside the lower chamber LC may be transferred together with the lowerchamber LC, and the apparatus according to an embodiment does notperform leak inspection on a battery cell B basis but may perform leakinspection in unit of the seat jig ZG in which a plurality of batterycells B are seated. That is, the upper chamber UC and the lower chamberLC that are in close contact with each other to face each other in theinspection stage IS may simultaneously seal the plurality of receivingspaces G inside the first sealing member S1 therebetween. The pluralityof receiving spaces G may be fluidly connected to each othersubstantially to share a set pressure according to pressure adjustmentcorresponding to ON/OFF of the pipe valve and may be controlled to a setpressure. Accordingly, respective inspection operations described belowmay be simultaneously performed on the plurality of receiving spaces G.

Referring to FIGS. 7 and 8, the vacuum chamber sealing operation S20 isperformed after the product placing operation S10. That is, when thelower chamber LC reaches an inspection position (the inspection stageIS), the upper chamber UC may descend toward the lower chamber LC and bein close contact with the lower chamber LC. Here, the upper chamber UCmay be in close contact with the lower chamber LC at a preset pressuresuch that the upper chamber UC and the lower chamber LC are sufficientlysealed with the first sealing member S1 therebetween. The upper chamberUC and the lower chamber LC may be in close contact with each other toface each other and thus the vacuum chamber VC is sealed, and then thepressure of the receiving space G in which the battery cell B isreceived may be controlled by ON/OFF of the various pipe valves drivenaccording to a control signal of the controller 100. Inspectionoperations described below may be performed under the controlledpressure.

Referring to FIG. 8, the before-vacuum thickness measuring operation S30is performed after the vacuum chamber sealing operation S20. That is,under a state in which the upper chamber UC and the lower chamber LC arein close contact with each other and thus the vacuum chamber VC issealed, the thickness measuring sensor TS of the upper chamber UC andthe battery cell B of the lower chamber LC are arranged at positionsfacing each other. Under this state, the thickness measuring sensor TSmeasures the before-vacuum thickness of the battery cell B according toa control signal of the controller 100. The measuring of thebefore-vacuum thickness may be performed under the relatively high firstpressure (ex. the atmospheric pressure). As an example, the thickness ofthe battery cell B may be measured under the first pressure (ex. theatmospheric pressure). As an example, the measurement of thebefore-vacuum thickness is performed under a state in which the upperchamber UC and the lower chamber LC are in close contact with each otherand thus the vacuum chamber VC is sealed, but the various pipe valvesfluidly connected to the receiving space G sealed by the upper chamberUC and the lower chamber LC are maintained at an off-state, andaccordingly, the receiving space G may be set to the first pressure (ex.the atmospheric pressure), which is the same as the outside of thevacuum chamber VC.

The thickness measuring sensors TS may respectively measure thethicknesses of the battery cells B at positions above the battery cellsB received in the respective receiving spaces G. The thicknesses of thebattery cells B measured by the thickness measuring sensors TS at thedifferent positions may be transmitted to the controller 100 togetherwith identification information of the relevant battery cells B.

The vacuum setting operation S40 is performed after the before-vacuumthickness measuring operation S30. That is, after the measuring of thebefore-vacuum thickness, vacuum setting may be performed in which thevacuum pipe valve VA is switching to an on-state with other pipe valvesturned off, and a vacuum fluid pump VAP fluidly connected to the vacuumpipe valve VA is driven to set the pressure of the receiving space G tothe relatively low second pressure. As an example, in the vacuumsetting, the pressure of the receiving space G may be set to a vacuumpressure lower than the first pressure (ex. the atmospheric pressure).In this case, the vacuum pipe valve VA may be connected to the upperchamber UC and connected to a position of the upper chamber UC betweenthe different receiving spaces G to simultaneously provide a negativepressure to the plurality of receiving spaces G. The plurality ofreceiving spaces G are sealed inside the first sealing member S1 betweenthe upper chamber UC and the lower chamber LC and set to and maintainedat a low pressure of the second pressure when the vacuum pipe valve VAis switched to an on-state.

The after-vacuum thickness measuring operation S50 may be performedafter the vacuum setting operation S40. Similar to the before-vacuumthickness measuring operation, in the after-vacuum thickness measuringoperation, each thickness measuring sensor TS arranged at a positionabove each battery cell B may measure the thickness of the relevantbattery cell B under vacuum in which the relatively low second pressureis maintained. The measured thickness information may be transmitted tothe controller 100 together with identification information of therelevant battery cell B. The controller 100 may compare information ofthe before-vacuum thickness with information of the after-vacuumthickness to determine whether swelling occurs, and transfer themeasured results to an operator to allow the operator to determinewhether swelling occurs.

The vacuum destroy operation S60 is performed after the after-vacuumthickness measuring operation S50. In the vacuum destroy operation, withthe other pipe valves turned off, the destroy pipe valve R is switchedto an on-state to release the vacuum state of the receiving space G andset the inside of the receiving space G to the relatively higher thirdpressure (ex. the atmospheric pressure) than the second pressure (thevacuum pressure). As an example, the pressure of the receiving space Gmay be set to the atmospheric pressure or the relatively high thirdpressure close to the atmospheric pressure. The destroy pipe valve R maybe on/off-driven to selectively connect the inside of the vacuum chamberVC to the outside of the vacuum chamber VC. When the destroy pipe valveR is switched to an on-state, the pressure of the inside of the vacuumchamber VC may be set to the third pressure (ex. the atmosphericpressure), which is the same as the outside. The destroy pipe valve Rmay be mounted at a position of the upper chamber UC between theplurality of receiving spaces G and fluidly connected to the pluralityof receiving spaces G and may simultaneously set the plurality ofreceiving spaces G to the third pressure (ex. the atmospheric pressure).

The TVOC measuring operation S70 may be performed after the vacuumdestroy operation S60. In the TVOC measuring operation, with the otherpipe valves turned off, the TVOC pipe valve VT is switched to anon-state to suck an internal gas of the receiving space G and measurethe concentration of TVOC from the sucked internal gas. When the TVOCpipe valve VT is switched to an on-state, the internal gas of thereceiving space G is forcibly introduced to a suction flow path throughthe TVOC pipe valve VT by the fluid pump (not shown) fluidly connectedto the TVOC pipe valve VT. In addition, the TVOC sensor VTS arranged onthe suction flow path may measure the TVOC concentration from theinternal gas forcibly introduced from the receiving gas G and transferthe measured results to the controller 100.

In the TVOC measuring operation, unlike the before-vacuum thicknessmeasuring operation and the after-vacuum thickness measuring operation,individual measurement is not performed on each battery cell B andcollective measurement for a plurality of battery cells B may beperformed on a seat jig ZG basis. That is, rather than determiningwhether each battery cell B leaks based on the measured results from theTVOC sensor VTS, it may be possible to finally determine whether a leakoccurs by determining whether a leak occurs with reference to swellingmeasurement obtained by measuring a before-vacuum thickness and anafter-vacuum thickness prior to the TVOC measurement, and by determiningagain whether a leak occurs with reference to the additional TVOCmeasurement results. The TVOC pipe valve VT may be mounted on the upperchamber UC and fluidly connected to the plurality of receiving spaces Gat a position of the upper chamber UC between the plurality of receivingspaces G, and the TVOC sensor VTS may measure the TVOC concentration ofthe entire gas forcibly introduced from the plurality of receivingspaces G.

The TVOC sensor VTS may transmit the measurement result to thecontroller 100, and the controller 100 may determine a leak occursdepending on whether a concentration higher than the reference value ismeasured based on information regarding the TVOC concentration, andtransmit the measured results to an operator to allow the operator todetermine whether a leak occurs. As an example, when the TVOCconcentration is higher than the reference value, it may be determinedthat the higher TVOC concentration occurs due to a volatile component ofthe electrolyte that leaks from a defective battery cell.

The normal/defective product determining operation S80 of the batterycell may be performed after the TVOC measuring operation S70. Thenormal/defective product determining operation may be performed by thecontroller 100 that receives the information regarding a thicknesschange measured in the before-vacuum thickness measuring operation andthe after-vacuum thickness measuring operation. That is, the controller100 may compare a before-vacuum thickness of each battery cell B with anafter-vacuum thickness each received from the thickness measuring sensorTS, determine whether swelling occurs to the relevant battery cell B,and determine that the battery cell B in which the after-vacuumthickness increases beyond the reference value compared to thebefore-vacuum thickness, that is, the battery cell B in which swellingoccurs is a defective battery cell.

In addition, the controller 100 may determine that a battery cell B is adefective battery cell depending on whether a TVOC concentrationdetected in the TVOC measuring operation is higher than the referencevalue. In this case, since the TVOC measuring is performed on aplurality of battery cells B on a seat jig ZG basis, whether a batteryis a normal/defective battery may be determined on a battery basis basedon whether swelling occurs to each battery, and the TVOC measurementresults may be utilized as additional information for determining theexistence of a defective battery.

The determination of a normal/defective battery may be performed by thecontroller 100 that receives measurement results from respectivesensors, that is, the thickness measuring sensor TS and the TVOC sensorVTS, or may be performed by an operator who receives the measurementresults from the controller 100. For the determination of anormal/defective battery to be performed by the controller 100, a cleardetermination reference needs to be set. As an example, a referencevalue with respect to a thickness difference between a before-vacuumthickness and an after-vacuum thickness may be prepared, and a thicknesschange exceeding the reference value may be determined as swelling (or aleak). For the TVOC measurement results, a reference value with respectto the TVOC concentration may be prepared, and a TVOC concentrationexceeding the reference value may be determined as a leak.

The vacuum chamber opening operation S90 and the product dischargingoperation S100 may be performed after the normal/defective productdetermining operation S80 of the battery cell. That is, as describedabove, after the leak inspection is completed, the upper chamber UC isdriven to ascend in a direction away from the lower chamber LC todischarge an inspection-completed battery from the inspection stage ISand open the vacuum chamber VC. In addition, the lower chamber LCreleased from the upper chamber UC is driven in one direction (theback-and-forth direction) to be away from the upper chamber UC, and theinspection-completed battery is discharged from the inspection stage IStogether with the lower chamber LC. The lower chamber LC that is removedfrom the inspection stage IS, after the seat jig ZG in which a newbattery is seated is replaced, may be re-introduced into a series ofinspection operations that begins from a product placing operation, forleak inspection of a new battery.

Though the present disclosure is described with reference to theembodiments shown in the drawings, these are provided as examples, andit would be understood by those of ordinary skill in the art thatvarious modifications and equivalents thereof may be made from theembodiments. Therefore, the scope of the present disclosure should bedefined by claims.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to an apparatus and a method forinspecting a leak of a battery cell that is rechargeable anddischargeable as an energy source.

1. An apparatus for inspecting a battery cell leak to inspect whether abattery cell leaks, comprising: a vacuum chamber including an upperchamber and a lower chamber and configured to set a receiving space to acontrolled pressure different from an external first pressure, the upperchamber and the lower chamber being arranged to face each other with thereceiving space for a battery cell therebetween and providing sealingfor the receiving space; a vacuum pipe valve fluidly connected to thereceiving space for the battery cell to set the receiving space to asecond pressure less than the first pressure; and a thickness measuringsensor configured to measure a before-vacuum thickness of the batterycell under the first pressure and measure an after-vacuum thickness ofthe battery cell under the second pressure.
 2. The apparatus of claim 1,further comprising a controller configured to determine whether thebattery cell leaks based on a thickness difference between thebefore-vacuum thickness and the after-vacuum thickness.
 3. The apparatusof claim 2, wherein the controller compares the before-vacuum thicknesswith the after-vacuum thickness and determines that a leak occurs in abattery cell in which swelling occurs.
 4. The apparatus of claim 2,wherein the controller compares a reference value set in advance withthe thickness difference and determines that a leak occurs in a batterycell in which the thickness difference exceeding the reference value ismeasured.
 5. The apparatus of claim 1, further comprising a totalvolatile organic compound (TVOC) pipe valve configured to suck aninternal gas from an inside of the receiving space for the battery cell;and a total volatile organic compound (TVOC) sensor arranged on asucking flow path of the internal gas to measure a concentration oftotal volatile organic compound from the sucked internal gas.
 6. Theapparatus of claim 5, further comprising a controller configured tosynthesize information regarding the before-vacuum thickness and theafter-vacuum thickness transmitted from the thickness measuring sensorand information regarding the concentration of the total volatileorganic compound transmitted from the TVOC sensor to determine whether abattery cell leaks.
 7. The apparatus of claim 5, further comprising adestroy pipe valve configured to set the receiving space for the batterycell to a third pressure higher than the second pressure, wherein theTVOC pipe valve provides a negative pressure lower than the thirdpressure to forcibly suck the internal gas from the inside of thereceiving space set to the third pressure.
 8. The apparatus of claim 7,wherein the receiving space is provided in plural, and the vacuum pipevalve, the TVOC pipe valve, and the destroy pipe valve are arranged in aposition of the upper chamber between the plurality of receiving spaces,fluidly connected to the plurality of receiving spaces, and set apressure shared by the plurality of receiving spaces.
 9. The apparatusof claim 1, wherein the thickness measuring sensor is provided at aposition of the upper chamber that faces the receiving space andarranged to face a battery cell inside the receiving space.
 10. Theapparatus of claim 1, wherein the thickness measuring sensor is anon-contact type eddy current sensor, wherein an insulating block isassembled in the upper chamber, the insulating block surrounding andinsulating the thickness measuring sensor.
 11. The apparatus of claim 1,wherein the thickness measuring sensor is provided in plural tocorrespond to the receiving spaces, respectively.
 12. The apparatus ofclaim 1, wherein the first pressure corresponds to the atmosphericpressure.
 13. The apparatus of claim 1, wherein a seat jig is assembledin the lower chamber, a plurality of receiving spaces being provided inthe seat jig.
 14. The apparatus of claim 13, wherein the apparatusperforms inspection on the seat jig basis.
 15. A method of inspecting abattery cell leak using an inspection apparatus including a vacuumchamber and a vacuum pipe valve for controlling a pressure of an insideof the vacuum chamber, the vacuum chamber including an upper chamber anda lower chamber, the method comprising: placing a battery cell to aninspection position such that an inspection stage is provided, in whichthe upper chamber and the lower chamber are arranged to face each otherwith a receiving space for the battery cell therebetween; sealing thereceiving space by lowering the upper chamber toward the lower chamber;maintaining the vacuum pipe valve in an off-state to maintain thereceiving space of the battery cell at a first pressure which is thesame pressure as before the sealing of the vacuum chamber and measuringa before-vacuum thickness of the battery cell under the first pressure;switching the vacuum pipe valve to an on-state to set the receivingspace of the battery cell to a second pressure lower than the firstpressure; and measuring an after-vacuum thickness of the battery cellunder the second pressure.
 16. The method of claim 15, furthercomprising determining whether the battery cell leaks based on athickness difference between the before-vacuum thickness and theafter-vacuum thickness.
 17. The method of claim 16, wherein thedetermining of whether the battery cell leaks includes comparing thebefore-vacuum thickness with the after-vacuum thickness and determiningthat a leak occurs in the battery cell in which swelling occurs.
 18. Themethod of claim 15, further comprising switching a destroy pipe valvefluidly connected to the receiving space for the battery cell to anon-state to set the receiving space to a third pressure higher than thesecond pressure; and forcibly sucking an internal gas from an inside ofthe receiving space set to the third pressure and measuring aconcentration of total volatile organic compound from the suckedinternal gas.
 19. The method of claim 18, further comprisingsynthesizing a thickness difference between the before-vacuum thicknessand the after-vacuum thickness, and the concentration of the totalvolatile organic compound to determine whether the battery cell leaks.20. The method of claim 15, wherein the placing of the battery cell tothe inspection position includes assembling a seat jig in the lowerchamber, receiving spaces for a plurality of battery cells beingprovided in the seat jig; and moving the lower chamber receiving theplurality of battery cells to a waiting position of the upper chamber.21. The method of claim 15, further comprising raising the upper chamberin a direction away from the lower chamber to discharge aninspection-completed battery cell.